Interpretive Handbook

Test
81743 :
Lysergic Acid Diethylamide (LSD) Confirmation, Urine

Lysergic acid diethylamide (LSD) is an extremely potent psychedelic ergot alkaloid derived from the fungus, Claviceps purpurea.(1) The drug LSD binds to serotonin receptors in the central nervous system and acts as a serotonin agonist.

The clearance half-life of LSD averages 3 to 4 hours. It takes 5 to 7 half-lives to clear 98% of a drug dose. Therefore, the presence of LSD greater than the lower limit of quantification (LOQ; cutoff concentration) indicates exposure to LSD within 1 day.(2)

LSD is metabolized to 2-oxo-3-hydroxy-LSD, which is present at concentrations 16 to 43 times higher than LSD, and is likely to be present in urine for up to 4 days after last exposure.(3,4)